Current training practices for bone-related procedures (e.g., orthopaedic surgery, dentistry, veterinary medicine etc.) in human and animal health, where bone is probed, drilled, cut, sawed, burred, or punctured or is manipulated to adjust or repair deformity or damage, relies almost exclusively on a master-apprentice model. In this approach, the experienced clinician performs the procedure with the apprentice observing, and over time the apprentice is allowed to engage in a progressively more advanced manner with the procedure. For the procedures discussed herein this is usually on living people or animals. While there are alternative approaches that rely upon various levels of simulation, they each have distinct disadvantages in the context of these procedures that rely heavily on accurate tactile and visual feedback; as a result, training continues to rely upon the apprentice approach during live procedures. This approach is high risk since any mistake by the apprentice can be catastrophic for the person or animal undergoing the procedure; there is limited operating room time under which such apprenticeship can be offered; and there is no mechanism that allows the trainee to repeat procedures multiple times in succession, experiencing how the procedure feels when performed both correctly and incorrectly, without negative consequences.
In terms of alternative approaches, the use of cadaveric specimens provides a realistic experience of the tactile feedback since it uses real bone, although almost all are from older people, which may not represent the typical patient population. The visual cues are also reasonably accurate for many of the procedures since the covering tissues need to be addressed in the similar way they would be in an actual procedure (the reduction of blood and other living related fluids notwithstanding). However, the challenge with cadaveric approaches is they are in limited supply, and expensive, so the expectation is that the trainee performs the procedure correctly, and only limited opportunities are provided. Thus the cadaveric approach does not lend itself to a training pedagogy that allows for repeated attempts at the same procedure in the same session and in a manner that allows for experiencing the tactile feedback of both correct and incorrect procedures. The high cost and low availability of cadaveric specimens is a trend in both the human case (where donation rates are low) and the animal case (where growing concerns over the treatment of animals has substantially reduced the availability of cadaveric specimens).
Current simulated bones are designed to look like bone but do not reproduce the tactile and structural properties of bone. These simulated bone materials are suitable for demonstrating the spatial relationships between bones and also for the spatial relationship between bones and various devices such as tools, implants, and screws but not for simulations of procedures and processes that act upon the bone through sawing, screwing, cutting, scraping, drilling, hammering, etc. that require specific bone-related material properties such as the strength, elastic modulus, bone density (e.g., cancellous/cortical bone), heterogeneity, variability and weight etc. Current synthetic bone models use a plastic exterior and foam interior construction that, while allowing for an accurate exterior look of real bone, does not accurately simulate the feel of real bone when acted upon.
Computer simulations provide visualizations of some bone-related procedures but currently there is limited availability of such simulations and those that are available do not allow for simulation of realistic loads experienced with real instruments and procedures during bone-invasive procedures so the tactile feedback does not feel like bone. Furthermore, they do not provide the opportunity to work with real instruments in such procedures, and therefore cannot train muscle memory or true three-dimensional visual cues. Computer simulations are best used for improving knowledge rather than improving skills.
There is a growing educational trend to move away from summative training methods that evaluate overall learning across a number of learning objectives at the end of a module, towards competency-based training that evaluates specific competencies, breaking down the learning objectives into specific units. Trainees must demonstrate mastery of each competency before they are allowed to proceed to the next competency. For competencies discussed herein that are high risk and have large health and safety concerns, the competency approach has obvious advantages since it allows for progressive demonstrated skill development. However, for the procedures discussed herein there is no low risk cost-effective and reliable way to train and test such competencies before trainees perform such procedures, to refresh their skills or to demonstrate continued competency in their ongoing certification and re-certification procedures.
Similar challenges are faced within the biomechanical testing of devices that are used with bone. Currently, cadaveric models are expensive and difficult to obtain and inconsistent so are often not suitable for the control of conditions and repetition needed in biomechanical testing. Simulated bone for biomechanical testing currently consists of foam blocks that are poor proxies for real bone and only a large amount of historical use and no viable alternative has allowed these materials to be used as proxies for bone in biomechanical testing. There exists a need for improved artificial bones that perform like mammalian bone when subjected to procedures and processes that act upon the bone through sawing, screwing, cutting, scraping, drilling, hammering, etc.